A kinetic study of the oxidation on H2S on gamma-alumina by SO2 following a modified Claus process at low temperature (373-473 K) was carried out. To the analytical data, at varying SO2 and H2S concentrations, several Langmuirian type expressions for the reaction rate were applied. The models were submitted to statistical and physical criteria to establish the best fitting of the experimental results. The resulting kinetic expression applied to sulphurized surfaces shows the chemical reaction between adsorbed species -one of them H2S dissociatively adsorbed- as the controlling step of the process. The reaction was also effected under integral regime, the obtained results confirming the validity of the proposed kinetic expression.